TopoJSON support

[mourner]

Lets discuss @mbostock's TopoJSON support for Leaflet (either as a plugin or in the core) here. cc @danzel @JasonSanford

[JasonSanford]

Some of @sgillies recent work with converting TopoJSON to GeoJSON with Python will likely help.

[mbostock]

+1! I'm guessing since Leaflet already supports GeoJSON, the TopoJSON client library, topojson.js should be usable out of the box. In particular, the topojson.object method for converting a TopoJSON object back to a GeoJSON object. Of course it’s always easier if Leaflet can take care of that conversion for you.

The TopoJSON client library also provides a mesh algorithm which is useful for computing boundaries on the fly, such as inter-state boundaries while excluding coastlines. That’s definitely not required to use TopoJSON, but it is quite useful in a number of mapping applications.

Let me know if I can offer any further advice.

[danzel]

We definitely need a plugin for this if we don't put it in core. Looks cool!

[JasonSanford]

Yep, seems easy enough. http://bl.ocks.org/4554134

Any strong feelings on core or plugin?

[danzel]

Feels like a plugin to me

[TheSisb]

I'm new to these parts of Github, but if it has the potential to improve performance as dramatically as suggested then it should be part of the core lib.

[tmcw]

👍 plugin. If it becomes a 'must-have' it should be core, but TopoJSON is a niche at this point and is a significant amount of code.

[mbostock]

The minified topojson.object method (which is all you'd need at minimum to convert TopoJSON to GeoJSON) is only 993 bytes, so that’s not a lot of code. But I have no opinion on whether or not to plugin.

[mourner]

I think it's so easy to use the topojson library out of the box with Leaflet that this can be considered done.